1. Field
The present disclosure generally relates to segmented tools having multiple pieces that are sealed together, and deals more particularly with a triple seal arrangement and related method allowing the integrity of the individual seals to be tested and monitored.
2. Background
Some tools comprise multiple pieces or segments that must be assembled, but which are required to function and perform function as a seamless, single tool. For example, in the aircraft industry, a large composite fuselage section may be laid up on, vacuum bagged and then autoclave cured on a generally cylindrical mandrel comprising multiple circumferential mandrel segments. The mandrel segments are assembled along seams. Following curing and de-bagging, the mandrel segments must be disassembled in order to allow release and removal of the cured fuselage section from the tool.
Each seam between the mandrel segments may be sealed with a substantially air-tight seal extending along joining surfaces of adjacent mandrel segments. Air leakage through any of one of these seals may reduce compaction pressure applied to the fuselage section during curing. A reduction in compaction pressure during curing due to an air leak may have an undesirable effect on the quality and/or performance of the cured fuselage section.
One proposed solution to the problem of seal leakage involves the provision of double seals along the seams between the mandrel segment seams. The double seals are arranged to form a chamber that may be used to perform a pass or fail leak test, however, the test does not indicate which of the double seals may have lost its integrity. If the test fails, indicating that the integrity of at least one of the seals may have been compromised, the tool segments must be disassembled, and the seals must be repaired or replaced, following which the mandrel segments must be reassembled and the leak test must be repeated. The process of disassembling/reassembling and replacing the seals is time consuming, labor intensive and may reduce production throughput and build rate.
Accordingly, there is a need for a method of sealing and testing the integrity of seals in segmented tools such as mandrels that allows continuous monitoring of seal integrity. There is also a need for a seal arrangement and testing method which will identify which, if any, of the seals are leaking and whether at least one seal has retained its integrity.